Pneumatically-controlled soil sampler



Dec. 29, 1953 E. e. Kwan-1T ET AL PNEUMATICALLY-CONTROLLED SOIL SAMPLER Filed May 5, 1949 Patented Dec. 29, i953 UNITED STATES TENT OFFICE PNEUMATICALLY-CONTROLLED SOIL SAMPL Elton G. Knight and John W. Miller, Los Angeles, Calif.

Application May 3, 1949, Serial No. 91,206

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without payment to us of any royalty thereon.

In structural operations, it frequently becomes necessary to determine the character of the earth and soil on which structural fundations are to be placed. Various methods and apparatus have been devised for the taking of such earth samples, but all of these are subject to various disadvantages, among which principally is the difficulty of obtaining representative samples Where the earth being sampled includes loose silt or sand, or the like.

One commonly employed method of earth sampling comprises drilling or washing holes down to the material to be sampled, and then pushing thin-walled steel tubing into the material with a steady downward motion. These tubes as customarily employed are from about two and one-half to about four feet 1n length with an inside diameter of from two to five inches, the lower edge being beveled and sharpened so that the cutting edge has a diameterof approximately 1.5 per cent less than the inslde diameter of the tube. The tube as thus ernployed is attached to an adapter head tted with a ball-check valve to allow Water in the tube to escape as the soil enters. It also creates a partial vacuum when the tube is being withdrawn, thus helping to retain the sample.

This typical equipment of the prior art is open to various objections that are inherent to all of these types of constructions and operation thereof. For instance, water, thick mud, and sand encountered as the tube is being pushed into the stratum being sampled enter the open end of the tube as it is lowered, often clogging the ballcheck valve, resulting in loss of vacuum necessary to compensate for that created in extracting the tube from the layer being sampled. Such undesired material as indicated above, which enters the tube before it reaches the stratum to be sampled, makes recovery of the sample di'icult and decreases the amount of the useful sample by as much as fty per cent, as frequently is experienced` in actual operations.

A further objection to this prior art equipment is the fact that in operation the Withdrawal of the tube and sample from the-stratum being sampled creates a vacuum which tends to suck the sampled soil out of the tube; and also, loss of sample frequently is experienced particularly where the sample is loose wet silt, by the sample being jarred from the tube by sudden starting of the hoist of the drill rig equipment on which the sampling tube is carried or because of jarring of the sample-carrying tube from any cause.

The present invention provides a simple and easily operated construction of an earth-sampling mechanism which completely obviates the foregoing, and other, difiiculties encountered in the operation of the conventional equipment for this purpose. Y

A further object of the invention is to provide a pneumatically-controlled sampler which is operated easily, which positively retains the desired sample in an undisturbed condition and which prevents the entry into the samples of unwanted materials, the improved construction therefore increasing very materially the percentage of desired sample recovered, and enabling the procurement of better samples especially where the vsamples are composed of silty materials.

Other objects and advantages of the improved construction will become apparent as the description proceeds, and the features of novelty will be pointed out in particularity in the appended claims.

The improved construction of the present invention is a pneumatically-controlled sampling device that uses the same steel tubing as described above that has been employed customarily. TheV invention involves a redesign of the adapter head, and the incorporation therein of two leather pump cups to obtain a tight connection with a flexible tubular hose leading to a source of pressure or vacuum. A piston, having one resilient pump cup permitting a tight connection with the steel tube for pressure only is connected to the adapter head by a high strength chain, which is adjusted for length so that under pressure the piston presents a conical outer surface for penetrating materials that are not to be sampled. Upon reaching the material to be sampled, the pressure is released, the tube is either pushed or driven into the soil, and as the material enters the sampler, the piston is carried upwardly to the top of the tube. The vacuum is applied immediately, and the sampler is withdrawn. A single pump cup on the piston permits the vacuum to be applied to the entire sample and substantially neutralizes the vacuum created between the bottom of the sample and the surrounding stratum when the sample is withdrawn.

With the foregoing general considerations in mind, reference may be had to the accompanying drawings which show a representative and exemplary modification of a construction embodying the features of the present invention. In the drawings- Fig. l is a fragmentary longitudinal .sectional elevation of an earth sampler embodying the features of the present invention, the view showing the piston in expanded position for penetrating overlying material until the stratum for taking the desired sample of earth is reached;

Fig. 2 is a View showing the position of the parts when the tubular sampler is filled with sampled material;

Fig. 3 is an elevation of the improved sampler of the invention partly in section, showing the sample of earth Vpartially extruded from the sampler tube;

Fig. 4 is a perspective view showing the adapter head and tube in disassembled relation; and

Fig. 5 is a perspective view showing details of the piston.

Referring more particularly to the drawings, reference numeral i represents a steel tubing of above-described character, the upper end of which is secured to an adapter head 9, and in which a piston ii is slidably mounted to normally close the lower end of the tube l. The outer surface of the piston il is beveled as indicated at i3 to form an earth-penetrating point i5, the inner periphery of the piston being recessed to receive a resilient cup-shaped packing or washer Il that is held in place by a locking ring I. rhe cupshaped washer l l may be made of leather or rubber, or other yieldable material. The piston ll is connected to the adapter head 9 by a highstrength flexible chain 2i that is adjusted for length so that the piston l i presents, when under pressure, a conical outer surface for penetrating earthy materials that are not to be sampled.

This pressure is applied to the interior of the tubular casing l by providing the adapter head S with an air passage `or duct 23 which 4has its inner end opening interiorly of the casing f'i and is threadedly Vfitted at its outer end with a connecting nipple 25 which receives an air hose El that leads to a suitable compressing means, not shown. The adapter head 9 is connected to the tubular casing l by screws cr other suitable securing elements, designated at 29, an annular shoulder 3l on the adapter head serving as an abutment for the upper end of the casing l. The lower periphery of the adapter head is recessed to receive oppositely disposed, cup-like yieldable packing gaskets 33, 35, which are positioned as shown on the drawings and retained by a locking ring 3l" threadedly secured around the inner end of the adapter head. The upper part of the adapter head is formed into a socket 39, which is adapted to receive actuating rod el ofthe driving and retracting mechanism, not shown, for the casing l, connection between Vthe socket 3S and actuating rod 4l being eiected by means of a pin 133 passed through registering holes in the socket 39 and rod l, as is shown at d5. Corresponding holes l and e8 are provided in the 4 casing l and adapter head 9, which holes come into registry when the shoulder 3| seats on the upper end of the casing l, for receiving the securing means 29.

In operation, when the equipment is assembled, the casing 'i' is forced into the ground where the sample is to be taken by suitable force applied to the adapter head 9 through actuating rod il and pin 43, while the piston ii is maintained in extended position by air under pressure in the space 5l between the piston and adapter head, conipressed air being forced into the space through the passage 23, the length of the chain being adjusted so that the piston Il reaches the lower end of the casing l' with the point l5 as the earthpenetrating means, while preventing the piston li being expelled from the casing. The pressure in the space 5l is maintained in excess of the pressure exerted by the earth against the piston so that the piston will be in extended position until the casing l engages the stratum to be sampled. IThe sealing gaskets i, 35 and 33 seal the space 5E against leakage of air around the piston Il and the adapter head 9.

rEhe lower end of the casing l is beveled to form a cutting edge 53. When the casing reaches the stratum to be sampled, the pressure in space 5l is relieved, and the compressing mechanism is reversed to apply suction through duct 23, the resulting vacuum in the space 5l retracting the piston i l as the casing is forced into the stratum being sampled. The retraction of the piston il under the vacuum behind it enables a sample 55 of the stratum to ill the casing l below the p-iston, the sample being drawn up into the casing through the combined action of the continue: downward movement of the casing and the suction produced by the withdrawal of the piston, this suction overcoming any tendency of the sample to be sucked out of the casing as the casing is withdrawn through the hole in the earth formed by its introduction. When the casing 'i has been withdrawn and brought to a convenient place for recovering the sample, pressure again is supplied behind the piston l l to expel the sample from the casing l in an undisturbed condition and in a suitable form for ready examination.

The improved construction of the invention permits a clean and undisturbed sample to be taken, free from extraneous or overburdening material, which is prevented from entering the casing, the sample being limited to the desired stratum. If this stratum contains sand or other loose or sedimentary materials, the improved sampling equipment of the invention permits the ready cbtaining of a representative sample of the stratum, notwithstanding the presence of such loose material. The resilient seals il, 3f and 33 render the interior of the casing l effectively air-tight and effectively prevent loss of either pressure or Vacuum.

While the 'above-described embodiment of the invention represents a typically preferred form thereof, it will be apparent that changes in structural details may be made without departing from the inventive concept; and it therefore will be understood that it is intended and desired to embrace within the scope of this invention such inodications and changes as may be necessary to adapt it to varying conditions and uses, as defined by the appended claims.

Having thus described our invention, what we claim as new and wish to secure by Letters Patent is:

l. A soil sampler comprising a tubular casing having a soil-cutting end, a closure head for the casing, a piston slidably mounted in the casing and spaced from the closure head, air-passage means for placing the piston under compression for forcing the piston from retracted position in the casing to expanded position closing the soilcutting end of the casing, the air-passage means also enabling application of vacuum to the space between the piston and the closure head to enable retraction of the piston into the casing responsively to sample-taking movement of the casing, and a flexible connecting cable attached to the piston and to the closure head and having a length enabling the piston to be expelled by air pressure in the space between the piston and closure to closing position at the soil-cutting end of the casing while preventing complete expulsion of the piston from the casing.

2. A soil sampler comprising a tubular casing having a soil-cutting end, a closure head for the casing, a piston slidably mounted in the casing and spaced from the closure head, air-passage means communicating with the said space and behind the piston enabling the piston to be placed under pressure of compressed air from a source thereof for forcing the piston from retracted position in the casing to extended position closing the soil-cutting end of the casing, the air-passage means also enabling application of vacuum to the said space for enabling retraction of the piston into the casing responsively to sample-taking m-ove-ment of the casing, a high-strength cable attached to the piston and tothe closure head, and having an adjusted length sufficient to enable the piston to be expelled by air pressure in the said space to closing position at the soil-cutting end of the casing while preventing complete expulsion of the piston from the casing, and sealing means on the piston and head for preventing leakage of air between such members and the casing.

3. A soil sampler comprising an elongated tubular casing having a soil-cutting head, a piston member slidably mounted in the casing, said piston member being formed to engage when in the extended position with said soil-cutting head and seal the lower end of the sampler casing, an adapter head for the casing forming a closure for the casing at its open end, means securing the casing to the adapter head, means secured to the adapter head to progressively advance and retract the casing relative to the soil to be sampled, a connecting cable between said piston member and said adapter, the length of said cable being sufficient when it is in a fully extended position to permit the soil cutting end of the sampler casing to be sealed by said piston member, and air passage means for effecting pneumatic actuation of the piston member whereby positive pneumatic pressure maintains the piston member engaged With said soil-cutting end and a reduction of pressure below that of the external surrounding pressure causes the retraction of the piston means into the casing to aid the retenti-on in the lower part of the casing of the sample of soil to be examined.

4. A soil sampler comprising an elongated hollow tubular casing having a cutting edge at its lower end, a piston member slidably mounted in the casing and provided with a conical surface adapted to form a closure extension of the cutting edge. an adapter head securely fastened to the casing and forming a closure for the casing' at its upper end, extensible means securing the piston to the adapter head, mechanical means secured to the head enabling progressive advancement and retraction of the casing relative to the soil to be sampled, and air passage means extending through the adapter head for effecting pneumatic actuation of the piston member to maintain the pist-on member in extended soil penetrating position, said air passage means also being capable of creating a suction behind the piston member causing retraction thereof into the casing for enabling the casing to receive an undisturbed sample of soil.

5. A soil sampler comprising a tubular casing having opposite ends, a cutting edge for the casing adjacent to one of the ends, a closure for the casing adjacent to the'opposite end, means rigidly connecting the closure to the casing, driving means for the casing attached to the closure and connecting the latter to a source of driving power, a movable piston mounted within the casing, flexible cable means connecting the piston to the closure, and air passage means extending through the closure and behind the piston for admitting air under compression behind the piston for expelling the pist-on outwardly through the closure to the cutting edge, the air passage means also enabling the air to be exhausd from behind the piston for retracting the piston into the casing, the flexible cable means connecting the piston to the closure having a length relative to the casing so that the said flexible means are expanded to full length thereof when the piston is expelled to extended position adjacent to the cutting edge.

6. A soil sampler comprising a tubular casing, a fixed closure for the casing adjacent to an end thereof, means connecting the xed closure and casing to a source of driving power for the casing, a movable closure for the casing slidably mounted therein, a flexible cable interconnecting the movable closure with the xed closure, and means extending through the iixed closure for injecting and withdrawing, selectively, actuating iiuid for the movable closure into the casing intermediate the fixed closure and the movable closure for selectively propelling the movable closure outwardly relative to the casing and retracting the movable closure into the casing responsively to the casing reaching a predetermined sampling depth into soil being sampled.

'7. In a soil sampler, a tubular casing having a cutting edge at one end, a closure for the end of the casing opposite to the cutting edge, means rigidly interconnecting the closure with the casing, means connecting the closure to a source of driving power, a movable piston mounted Within the casing, flexible means connecting the piston to the closure, and air passage means extending through the closure for applying pneumatic pressure to the piston for forcing the piston outwardly relative of the casing to a position adjacent to the cutting edge at fully extended length of the iiexible connecting means, the latter means restraining the piston at such position against further outward movement relative to the casing, the said air passage means also enabling exhaustion of air from the casing between the piston and closure for enabling retraction of the piston into the casing and retention of a soil sample in the casing.

8. In a s-oil sampler, a tubular casing, a closure for the casing fixedly secured thereto, a second closure for the casing reciprocable relative thereto, flexible means connecting the said c10- sures, the said iiexible means being extensible to full length responsivel'y to movement 'of the reciprocable closure outwardly relative to the casing while anchoring the reciprocable closure against complete expulsion from the casing, 5,

means connecting the fixed closure to a source of driving power for the casing, andy air passage means extending through the xed closure and opening into the casing intermediate the fixed closure and the reciprocable closure, the air Vpas sage means enabling selective application of pneumatic pressure behind the recprocable closure for blowing the closure through the Vcasing to the full length of the iiexble means connecting the flexible closure to the fixed closure and also evacuation of air from the casing behind the reciproeable closure for withdrawing the latter into vthe casing responsively 'to the casing being 8 dri-ven bythe source Aof power lto ya predetermined sampling depth in soil to be sampled.

ELTON G. KNIGHT. JOHN W. MILLER.

References Cited .in the file of this patent UNITED STATES PATENTS Number Name Date 2,283,650 Sanborn May 19, 1942 2,373,323 Macready Apr. i0, 1945 2,376,366 Lawlor et al May 22, 1945 2,382,992 Harris Aug. 21, 1945 2,458,631 Parks Jan. '11, 1949 FOREIGN PATENTS Number Country Date 838,716 France Dec. 16,1938 

